Telephone system.



No. 785,678. PATENTED MAR. 21, 1905.

I. KITSEE.

TELEPHONE SYSTEM. APPLICATION rum FEB. 24. 1902.

4 SHEETS-SHEET 1.

III I Y/IIIAEHI 1 M, I M

PATENTED MAR. 21, 1905.

I. KITSEE. TELEPHONE SYSTEM. APPLICATION FILED FEB. 24. 1902.

4 SHEETS-SHEET 2.

E. .q a. MW

mzr mr r' No. 785,673. PATENTED MAR. 21, 1905. I. KITSEE.

TELEPHONE SYSTEM.

APPLIOATION FILED P3131 24. 1902.

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N0..7s5,67s. v PATENTED MAR. 21, 1905.

f I. KITSEE.

TELEPHONE SYSTEM- APPLICATION FILED FEB. 24. 1902. 4

4 SHEETS-SHEET 4.

Patented March 21, 1905.

PATENT OFFICE.

ISIDOR KITSEE, OF PHILADELPHIA, PENNSYLVANIA.

TELEPHONE SYSTEM.

SPECIFICATION forming part of Letters Patent No. 785,673, dated March 21, 1905.

Application filed February 24, 1902. Serial No. 95,281.

To (1. 1071/0111, it Duty concern.-

Be it known that I, ISIDOR Krrsnn, of the city and county of Philadelphia, State of Pennsylvania, have invented certain new and useful Improvements in Telephone Systems, of which the following is a specification.

My invention relates to improvements in telephone systems, and has more special reference to systems wherein two or more outlying subscribers circuits are centered in one exchange and are provided therein with a common source of electric energy.

As much as the systems of to-day are improved their arrangements are still subject to manifold disadvantages, and it is the aim of my invention to overcome these disadvantages and to produce a system having improved features, as follows:

First, secrecy. In the central arrangement of to-day the operator can listen to the conversation of two'subscribers connected for the purpose of intercommunication at any time she may desire. To subscribers this fact is a great annoyance and I therefore have eliminated this objection, and my invention assures positive secrecy in so far that it makes it impossible for the operator to break in on lines connected for intercommunication.

Second, assurance of calling. To-d'ay the subscriber calling has no means of ascertaining if the operator at the exchange has called or, as the technical term is, has rung up the second subscriber, and this uncertainty often makes the subscriber calling impatient and unjust. \Vith the system as later on to be described the ringing up of the subscriber called is automatically brought to the notice of the subscriber calling.

Third. To-day the operator has it in'her power to ring up the subscriber called for for such length of time as she desires. In my system the time of the ringing up lays entirely with the subscriber calling, and he does not need to depend in this respect upon the operator.

Fourth. \Vith the systems of to-day disputes often arise between the subscriber and central on account of the number of calls and the time for each call. \Vith my system the calls are automatically registered through the action of the subscriber himself.

Fifth. To-day from five to seven distinct operations are necessary to connect two subscribersclosing the listening-key, making busy test, inserting plug in jack of callingline, releasing listening-key, closing ringingkey, releasing ringing-key, and inserting plug in jack of circuit to be called--and if the subscriber called does not answer at once the operation with the ringing-key has to be repeated.

As soon as the supervisorylamps show that both subscribers have finished conversation then the two plugs of the subscribers have to be removed from the switchboard, or, as it is technically called, the switchboard has to be cleared of the two plugs. In my system it is only necessary for the operator as soon as she sees her plug-lamp light to place the plug at adesignated point on her desk and then after ascertaining the wishes of the subscriber to place this plug in contact with the jack of the subscriber to be called. All other operations are automatically performed.

It .is readily seen that with this system an operator may be enabled to attend to double the number of subscribers circuits as with the systems now in use.

From the description and drawings it will also be seen than in my system the wiring is far less complicated than in the systems to-day in use and contains a lesser number of devices, and therefore the liability of disorder is greatly lessened.

Referring now to the drawings, in which similar characters indicate similar parts, Figu re 1 is a front elevation of one of the operators switchboards and desks. Fig. 2 is a vertical section through one of the operators switchboards, showing the same in use from either side. Fig. 3 is a plan view of one of the jacks in one of the switchboards with the upper shell removed, showing the parts in their normal positions. Fig. i is a similar view to Fig. 3,

only showing a plug inserted in one end. Fig. 5 is a transverse section through one of the Fig. 6 is a vertical longitudinal section Fig. 7 is a longijacks. through one of the acks.

tudinal section through one of the plugs. Fig. 8 is a diagram of the telephone;exchange. Fig. 9 is a diagram illustrating" three subscribers stations and their connections at the exchange. Fig. 10 is a diagram showing one subscribers station and its connection in the exchange.

a represents the receiver-lever within the subscribers station.

6 is a contact-point electrically connected with the ground 0.

al is a contact-point electrically connected to one terminal of the primary f of an inductorium.

g is the secondary of the inductorium, in which the receiver is placed.

it is the transmitter, and j is the bell.

1 and 3 are the main wires leading from the subscribers station to the exchange.

is a common battery to which the wire 3 leads.

Z is an electromagnet placed in series in the wire 3.

m is a contact-point; at, the armature of the electromagnet Z.

q is the electric-light board, which has the openings rformed through the same, in which openings are placed electric lights 8, which lights are in a circuit formed by wires leading from the contact m, through a common battery 1), through the light, and back to the armature a.

A is one of the operators switchboards and desk.

B represents the switchboard, and G a desk upon each side of the same.

D represents the jacks in the switchboard, each of which jacks is composed of a soft-iron core D, which passes longitudinally through the same, and the rod D, which normallyprojects a slight distance from the core D. The central portion of the core D is cut away, so as to expose the rod D, and extending from this rod in the center is the pin D", which normally lies in contact with a plate D, insulated from the plug D.

D is a pin extending upward from the rod D in the center, and D" represents springs connected to the pin and extending out from each side of the same andsecured to the plug at each end for the purpose of holding the rod 1) in the center.

D is a semicircular shell secured below the plug D and insulated therefrom.

D is a semicircular shield arranged above the core D and insulated therefrom.

E is one of the plugs which consists of the electromagnct E, provided with the soft-iron core a, which has the two soft-iron face-plates e and 0 and thesoft-iron shell E in magnetic contact with the face-plates efor the purpose of concentrating the lines of force at that end which is provided with the face plate 0 Around this core is wound the coil 6 This plug also consists of the outer conducting shell E insulated from the magnetic shell F is an induction-coil composed of the primary coil F and the secondary F.

F is a soft-iron core around which the two coils are wound.

F is a pivoted armature adapted to be attracted by the core F when energized, and F is acontact-point with which the armature F is adapted to make contact. At the opposite end of the core is arranged a pivoted armature F, which is adapted to make contact with the point F when attracted by the core.

G is a second induction-coil, of which Gr is the primary and G the secondary.

Gr is the core around which the primary and secondary are wound.

G is a pivoted armature adapted to be normally in contact with the point G", but to be pulled away from the same when the core G is energized.

G is a pivoted armature arranged at the opposite end of the core G", and when said core is energized said armature is adapted to make contact with the point G.

C represents openings formed through the operators desks C, and underneath these openings are arranged the springs I, which make contact with the contacts J when the plugs E are removed from said openings, as will hereinafter appear.

H is a battery included in the wire leading from spring I to the contact F. i

K is the desk electric light.

L is an electromagnet, and O is a battery, both of which are included in the circuit extending from contact G to armature G.

M is an armature adapted to be attracted by the magnet L, and N is a step-by-step indicating device adapted to be actuated by armature M.

P is an electromagneto-ringing device, and Q is the ground with which it is connected.

R is thesocket in which the plugs are placed to connect any one of the lines with the operators phone. This socket consists of the metallic shell R, which is adapted to make contact with the shell E of the plug, and inside of the shell R and insulated therefrom is the metallic plug S, which is adapted to make contact with the core of the plug.

T is the operators receiver, T the transmitter, and T is the inductorium of the op erators telephone, and T is the operators battery.

I will first describe the connection and wiring at the subscribers station, as is more fully illustrated in Fig. 10. I have in my arrangement, as illustrated, omitted the branch circuit containing the alarm and the condenser as usually employed in the systems of to-day, and 1 leave one line of the metallic circuit normally disconnected in its entirety from the hook-lever manipulated through the removalarm-bell to be used with the interrupted current. In fact, Iprefer to useahighly-inductive contrivanceone which retards greatly the flow of induced currents,so as to retard as much as possible the flow of earth-currents through that branch of the circuit which is normally connected through the lever with the ground. In the case where the polarized bell of to-day is .replaced by a device such as described the source of electricity P, which is grounded at Q, can then be either a direct and straight or interrupted current; but, if it is desired, this part of my invention may be omitted and the bridge as usually employed may be replaced.

The drawing Fig. 10 clearly illustrates the circuit, consisting of wires 1 and 3, as normally broken, because the wire 3 normally disconnects from the wire 1 and on'lyconnects therewith through the lever a when the receiver .2 is removed, and this lever comes in contact then with the contact (Z, which is the terminal of the line-wire 3. This line-wire contains in series the transmitter it and the primary f of the inductorium, the secondary g of which is connected to the receiver 2. The wires 1 and 3 form the circuit of the subscriber centered in the exchange, and the wire 3 is therein connected to the common battery A feature distinguishing this invention from the systems of to-day consists in the employment of a light-board and in the position of the same relative to the different switchboards and operators attending thereto.

I omit entirely the supervisory lamps of the present systems and substitute therefor the light-board, wherein each subscribers circuit is provided with an annunciator, preferably in the shape of an electric lamp, and this lampcircuit is preferably placed in a local circuit adapted to be operated by a relay placed in series in the subscribers circuit. The lightboard is placed at right angles to the switchboards, so that the operators attending to said switchboards can, through a slight movement of the head, readily ascertain which of the lights on this lightboard are lighted. The light-board presents for this purpose a double frontthat is, the lights in this board can be distinguished from both sides, (front as well as rear,) as is clearly illustrated in Fig. 8, in which 1 represents the light-board, r the openings, and s the electric lights in same, and in which A represents the diflerent switchboards, and X the positions of the different operators attending to said switchboards. The function of this light-board is to notify, through the state of the different lamps it contains, the status of the different circuits connected thereto, if said circuits are busy or if said circuits are idle. The lighting of a lamp indicates that the circuit connected thereto is employed and can therefore not be used by any of the operators for the purpose of connecting the same to a calling-subscriber. The light-board therefore takes the place of the so-called testing of to-day and makes unnecssary that operation of the operator which to-day pertains to the testing of the line. The operator having a call for a certain line looks up to the lightboard and ascertains if the circuit of the called-for subscriber is busy or not. If the lamp designating the number of the desired subscriber is not lighted, the circuit is not busy and the connection can be made. If, on the contrary, the lamp designating his number is lighted, then the circuit is busy and the connection cannot be made.

Each lamp carries on each side the number of its subscriber, and the opening may also be provided, if necessary, with a magnifyingglass, and it is obvious that with such arrangement the operator can easily ascertain by a mere look at the board if the number desired by her is busy or not.

The present invention also consists therein that each subscribers circuit has connected thereto in series, at the desk of the operator in charge of said circuit, the primary of an inductorium, the secondary of which is in inductive relation to the plug-cord, with which each of said circuits is provided.

In the experiments carried out for the purpose of ascertaining the necessary resistance and inductive values between primaries and secondaries I found that it would beimpractical to give the secondary a high-resistance value if this secondary should be connected through the plug to the circuit called, an operation which will later on be more fully described, and as a result of these experiments I prefer the arrangement as illustrated in Fig. 10, in which the primary of the inductorium connected in series to the subscribers circuit is provided with a secondary of high inductive value and wherein this secondary is connected in series with a high inductive secondary of a second inductorium, the lowresistance primary of which is connected to a plug-circuit. In other words, I make use of two induction coils or transformers, the first induction-coil being in reality a step-up and the second induction-coil being in reality a step-down transformer. In Fig. 10 this arrangement is illustrated as to consist of the step-up transformer consisting of the core F, the primary F, and the secondary F and the step-down transformer consisting of the core G the secondary G, and the primary G The primary F of the first or step-up transformer is connected in series to the circuit 1 3, and the secondary F of this transformer is connected in series to the secondary G of the second or step-down transformer, the primary of which is connected to the plugcircuit.

A further feature of this my invention consists therein that the plug constitutes an electromagnet andtwo conducting parts insulated from each other, each part connected to one contact of the plug-circuit forming the terminals of the primary G This plug E, as illustrated in Fig. 7, includes the electromagnet E, consisting of the softiron core 0, provided with the two soft-iron face-plates e and 0 and the soft-iron shell E in magnetic contact with the face-plates c for the purpose of concentrating the lines of force at that end which is provided with the end plate 0. Around this core is wound the coil a The plug E also consists of the outer conducting-shell E insulated from the magnetic shell E To this outer shell is connected, as said above, through the cord, one terminal of the primary G the other terminal of which is connected to the face-plate or its equivalent, the face-plate 0 in electrical contact with the faceplate a through the core 0.

The present invention also contemplates an arrangement whereby the ringing-circuit is automatically connected to the circuit called through the insertion of the plug. This arrangement is clearly illustrated in Fig. 10. P designates the source of ringing-current, which is grounded with one terminal at Q. A branch at the other terminal connects with a contact-point F in proximity to the armature F of the core F of the inductorium F. This armature is in electrical contact with the armature G" of the inductorium G, and in proximity to this armature is the contact G connected through the plug-circuit with the outer shell E of the plug E. N0rmallythat is, when the circuit to which the inductorium F belongs is idlethe armature F is drawn by its spring out of connection with the contact F; but the armature Gr is normally connecting with the contact G Should now the subscriber of the circuit consisting of the wires 1 and 3 remove his receiver from the hook, thereby closing the circuit, then the core F will be energized,thearmatureF will be drawn toward that core and in contact with the point F", closing the circuit consisting of ground Q, source of current P, contact F armature F, armature (i contact G and shell E of the plug E, and if, as will later on be more fully described, the shell Fj connects through the insertion of the plug with the grounded circuit-wire of the subscriber called then it is obvious that the generated current in P will find a path through the circuit just described and the grounded circuit-wire of the subscriber called.

In the general description, later on to be given, I will set forth the manner in which the ringing-circuit is broken as soon as the subscriber called has taken his receiver from the hook.

A further provision of the present invention consists therein that the calls are automatically registered. This arrangement is illustrated in Fig. 10 and consists of electromagnet L, provided with the armature M and ratchetwheel N in proximity to that part of the armature adapted to move this ratchet-wheel one or more points, as desired, through the energizing of the core of the electromagnet L. The coil of this electromagnet is connected to the circuit consisting of the battery 0, armature G, and contact-point G of the inductorium G. Normally this circuit is open, for the reason that the armature is drawn from its contact G by its spring; but when through the insertion of the plug (as will later on be fully described) the same connects with the circuit called and the subscriber of this circuit answers by removing his receiver. Then the core of the inductorium G will be energized and the armature Gr will be drawn upward and in connection with the contact G closing the circuit containing the elcctromagnet L, whereby the armature will be drawn toward its core and will manipulate the ratchet-wheel. This ratchet-wheel connects with any of the well l nown registering devices, and as it is the practice to illustrate a registering device by showing only the mechanism actuating the same and the ratchet-wheel I do not deem it necessary to illustrate in the drawings or describe in the specification a complete registering device, as the construction of such devices does not form the subject-matter of this my invention and is well understood by persons versed in the art.

I will now describe the switchboard. Both sides of the same can be used in the connection of subscribers, and therefore each is provided with the necessary operators desk, as is well illustrated in Fig. 2, wherein an operator is stationed on each side of the board. In this figure the center partition of the switchboard is designatcd by the letter B, and this center board is adapted to carry the different circuits designed to be connected to the different jacks. To this center board are also secured the spring-jacks D, with their shields D preferably in the shape of a semicircle, as illustrated. Thecenter board is closed on each side with an end board, (designated in the drawings by the letter A further feature of the present invention is the construction of the spring-jack. This spring jack embraces the following parts, (illustrated in detail in Figs. 3, l, 5, and 6:) the core of soft iron D, provided with the movable pin D longitudinally centered through the two springs D, connected to the pin-head D This movable pin is provided with the contact D normally in contact with the contact-plate D", secured to but insulated from the soft-iron core. also of the semicircular conducting-piece D in proximity to but insulated from said core. The contact-plate D* is provided with means to connect thereto one line of the subscribers circuit, and the soft-iron core is provided with means to connect thereto the other line of said circuit. The second line of the circuit is connected to the semicircular shell D As long as the contact D connects with the contact-plate D* that part of the circuit centered in the exchange is unbroken; but as soon as through the insertion of the plug E the pin D is pushed inward, breaking the contact between D and D, the circuit is broken and the plug-circuit may be made part of the subscribers circuit.

My invention therefore consists of the features and arrangements heretofore mentioned and hereinafter to be described, and particularly pointed out in the claims following this specification.

I will now describe the mocha-s ope mach: of my invention, taking for granted that the subscribers station is provided with an arrangement, as illustrated more specially in Figs. 9 and 10. I have in these figures, as was clearly stated in the description of the drawings, omitted the permanent connection of one of the circuit-wires through a condenser and alarm device with the lever 60, and I have connected this lever with the interposition of an alarm device to the ground C; but it is obvious that the usual arrangement may be used and the ground entirely dispensed with. Normallythat is, when the circuits are idle-the flow of the battery Z: is interrupted because one of the line-wires -in the drawings the line-wire 3-is out of electrical contact with the second linewire-in the drawings the line-wire 1-and with the exception of this break the circuit is a continuous one, as follows: commencing at the break in the subscribers station, as in Fig. 10, contactzil, primary of inductorium f, transmitter 7t, wire 3, common battery k, coil of clectromagnet Z, soft-iron core D, movable pin D contact D, contact-plate D*, of the spring-jack of the first switchboard, passing then to the spring-jack of the second switchboard if more than one switchboard is in the circuit, where the connection is the same as in the spring-jack just described, and from the contact-plate l) of the spring-jack of the last switchboard to one terminal of the primary F of the inductorium F, the other terminal of which is connected to the semicircular shell D of the spring-jack of the last switchboard, and connects then to the semicircular shell of the spring-jack of the switchboard preceding, till the semicircular shell of the spring-jack of the first switchboard is reached, where the same connects with the second line-wirein the drawings the line-wire 1connected at the subscribers station to the lever a in electrical connection through contact Z) and alarm with The spring-jack consists l the ground 0.

It is now supposed that the subscriber No. 1 wishes to communicate with the exchange. He removes, as usual, the receiver z from the hook (0, thereby bringing this lever or hook in contact with the point (Z. This closes the subscribers circuit, and the currentflow of the battery Zr has a continuous path, as is illustrated in Fig. 10, from the positive pole of said battery through wire 3, transmitter it, primary of inductorium f, contact (Z, lever a, line-wire 1, through the shells D of the different spring-jacks of the different switchboards, the primary F of the inductorium F, the different spring-jacks, the coil of electromagnet L, back to the negative pole of said battery. In Fig. 9 the coils of electromagnets Z are placed in the line 1 instead of the line 3, as illustrated in Fig. 10. This difference of placement does not alter the principle or working of the arrangement and only illustrates the flexibility of the system described. As soon as the contact between (Z and a at the subscribers station is established the electromagnet Z is energized through the How of the current, and in consequence the armature a is brought in contact with the pointm, thereby closing the local circuit containing the hatteryp and the lamp .9 of the light-board 9. At the same time the core F of the inductorium F will also be energized, and in consequence thereof the armature F will be brought in contact with the point F thereby closing the circuit containing the battery H, the operators lamp K, with its shunt I, and the coil 0" of the plug E; but at the same time the armature F will be drawn in contact with the point F which point is in contact with one terminal of the ringing-generator P. The lighting of the two lamps s in the light-board and K at the operators desk will at one and the same time first notify every operator in the room that the particular circuit is busy and, second, notify the operator having charge of this circuit that the same is calling, and the current-flow through the coil will energize the core (2 of the plug E. The operator being aware through the lighting of the lamp that the subscriber is calling removes the plug E of this particular circuit from the opening, in which it is held norn'ially in an upright position, and places it face downward in the listening-jack R, as is clearly illustrated in Fig. 2 by the left-hand operator and as is also illustrated in Fig. 9, wherein the circuit No. 3 is illustrated as in the act of calling and wherein the plug of said circuit is placed in the operators listening jack. The removing of the plug from its place allows the spring shuntarm I to connect with the contact J, thereby shunting the lamp K and extinguishing the same. When the lamp K is shunted, the circuit will be from the battery H to the contact F armature F, coil E of the plug E, contact J, arm I, and back to the battery H. The operator ascertains now the circuit number desired and having ascertained this number looks at the light-board to find out if the same is busy or not, and if the desired number is idle she inserts the plug E in the springjack denoting this circuit, as is clearly illus trated by the right-hand operator in Fig. 2 and in Fig. 9, wherein subscriber No. l is illustrated as called up and wherein the plug of circuit No. 2 is placed in the jack of circuit No. 1, thus indicating that circuit No. 2 was calling for circuit No. 1. It was clearly set forth in the description of the drawings that the plug consists in part of an electromagnet, and the insertion of the plug will there- 5 fore result therein that the same is drawn tightly at the face-plate of the jack in which it is inserted and will through this operation uncenter the pin D thereby breaking the contact between it and the contact-plate I). At the same time it will connect that part of the circuit called connected to the semicircular shield I) of the jack through the plug-shell E with one terminal of the primary Gr of the plug-inductorium G and will connect that part of the circuit called which is connected to the soft-iron core of the jack through the contact of the same with the core of the plug with the other terminal of said primary. The circuit called therefore will, as in Fig. 9, consist of the ground a, the alarm ,1, contact 6, lever a, wire 1, coil of electromagnet Z, semicircular shell D plug-shell E, that wire of the plug-cord connected to said shell and contact G respectively, contact G armature G, armature F, contact F ringing source P, and ground Q. As long as the subscriber called does not answer by removing his receiver that part of his circuit consisting of point (Z, primary f of receiver, transmitter 71, wire 3, and battery 71; is cut out and his alarm or other annunciator 7' is actuated by the ringing-current. Should the subscriber called answer by removing his receiver from the hook, then this hook will contact with the point (Z, breaking the contact with the grounded circuit containing the alarm. This alarm will therefore cease to ring and the following circuit will be established: lever a, wire 1, coil of electromagnet Z, shell I) of spring-jack, shell E of the plug, primary G" of inductorium Gr, core 6 of the plug, soft-iron core I) of springjack, battery KI, wire 3, transmitter it, primary f, and contact (Z. Through the flow of this current the core of the electromagnet Z will be energized, the ari'nature n will contact with the pointy/t, and the lamp 6 of the light-board Q will light. So,also, will the core G of the inductorium G be energized, drawing away from its contact G the armature G, thereby breaking the electrical connection with the circuit containing the ringing alarm. Through this operation all the connections of the circuits between it and the ground are broken. At the same time the armature G will be drawn in contact with the point (i and the circuit containing the battery 0 and electromagnet L will be established, operating the armature M and through it the ratchet N, which ratchet ogerates the meter device. The communication between the circuit called and the circuit calling is now established through the inductoriums F and G.

In the switchboard with which I experimented I used seven cells for the energizing of the plug, and I found that the contact between the plug and the jack-core was firmly enough established not to be broken through the falling of the other plugs.

I have carried on communication between two circuits through substantially the arrangement as illustrated in the drawings and described above, and I have found that this arrangement is even to be preferred to the arrangement as now practiced, wherein the two circuits communicating are connected in series with each other and wherein the current of the common battery flows to both circuits in series. One of the reasons for preferring this arrangement is that the high potentials due to the inductive action in the secondary are better transmitted over the wires of the second circuit than the slight variations of the primary current due to the varying resistance of the transmitter. These experiments were carried out with the help of two assistants, and the correctness of each of the arrangements was thereby established.

As long as communication lasts the plug will remain in connection with the springjack, and to guard the same more elficiently against other dropping plugs the upper part of the jack is provided with a semicircular shield D When the party calling replaces his receiver on its hook, then the electromagnet Z and the core of the inductorium f and the core of the plug E will be demagnetized. The plug will break its connection with the spring-jack and will, guided by the weight with which the plug-circuit is usually provided, return to its normal place, and the lampsof the light-board will be extinguished; but the lamp of the circuit called will be lighted till the party called has also replaced his receiver.

Such in broad outlines are the arrangements and devices for the system embodying my invention. It is believed that with these arrangements all possible exigencies are met, and should the exchange provided with this system also be provided with so-called trunklines connecting one exchange to the other then it is best that the circuit of these trunklines should be a normally closed one.

I have enumerated different novel devices and arrangements embodied in my invention. At a first glance it may seem that these devices and arrangements are entirely apart and independent of each other, yet to persons versed in telephone-exchange work it will be quite apparent that the system as such to be efiicient and complete has to embody every one of the features enumerated, and the entire structure represents one undivided system improved at ditterent points, the various devices and arrangements being interdependent upon each other.

Having now described my invention, what I claim as new, and desire to secure by Letters Patent, is

1. In a telephone system wherein two or more outlying circuits center in one exchange, a switchboard, an operators desk for said switchboard, an inductorium at said desk for each of the circuits in the charge of the operator at said desk, the coils of which inductorium are conductively independent, one of the coils of each inductorium being at all times electrically connected to its outlying circuit, and a connecting-plug also at said desk for each of said circuits and in inductive relation to said coil.

2. In a telephone system wherein two or more outlying circuits center in one exchange, a switchboard, an operators desk for said switchboard, an annunciating-lamp for each of the circuits in the charge of the operator at said desk, a shunt-circuit related to each of said lamps, means for lighting said lamps through the closing of the circuits at the outlying stations, and a connecting-plug for each of said circuits operatively related to the lamp thereof, said plugs being adapted to extinguish the lamps of the respective circuits by the removal of the plugs from their normal positions in the desk, whereby said shunt-circuits are established around said lamps.

3. In a telephone system wherein two or more outlying circuits center in one exchange. a switchboard, an operators desk for said switchboard, an inductorium at said desk for each of the circuits in the charge oi the operator at said desk, the primaries of said inductoriums being normally connected to their respective circuits, a second inductorium one coil of which is connected to the secondary of the first-mentioned inductorium, and a plug connected to the terminals of the other coil of the second inductorium for connecting said terminals with a second outlying circuit.

L In a telephone system wherein two or more outlying circuits center in one exchange, a switchboard, an operators desk for said switchboard, an inductorium at said desk for each of the circuits in the charge of the operator at said desk, a circuit containing a source of current, an annunciating-lamp, means influenced by said inductorium for closing said circuit, a plug, a seat therefor, and means for extinguishing the lamp by the removal of the plug from its seat.

5. In a telephone system wherein two or more outlying circuits center in one exchange, a switchboard, an operators desk for said switchboard, an inductorium at said desk for each of the circuits in the charge of the operator at said desk, a ringing-circuit, a signaling mechanism at a subscribers stat-ion, and means influenced bysaid ind uctorium forclosing said ringing-circuit to operate said signaling mechanism.

6. In a telephone system wherein two or more outlyingcircuits center in one exchange, a switchboard, an operators desk for said switchboard, an inductorium at said desk for each of the circuits in the charge of the operator at said desk, a ringing-circuit, a circuit containing a source of current and an annunciating-lamp, and means influenced by said inductorium for closing the ringing and lamp circuits.

7. In a telephone system wherein two or more outlying circuits center in one exchange, a switchboard, an operators desk for said switchboard, an inductorium at said desk for each of the circuits in the charge of the operator at said desk, a second inductorium in inductive relation to the first-mentioned inductorium, a ringing-circuit, a plug for connecting said second inductorium with a second outlying circuit, and means influenced by said second inductorium for closing and opening the ringing-circuit through said plug.

8. In a telephone system wherein two or more outlying circuits center inone exchange, a switchboard, an operators desk for said switchboard, an inductorium at said desk for each of the circuits in the charge of the operator at said desk, the primaries of said inductoriums being normally connected to their respective circuits, a second inductorium in inductive relation to the first-mentioned inductorium, and a plug connected to one of the coils of said second inductorium for connecting the latter with the outlying circuit.

9. In a telephone system wherein two or more outlying circuits center in one exchange, a switchboard, an operators desk for said switchboard, a connecting-plug at said desk for each of the circuits in the charge of the operator at said desk, an electromagnet in the circuit of said connecting-plug, a pair of armatures for said electromagnet, a ringing-circuit in which one of said armatures is included and by which said circuit is opened and closed, and a circuit including the other armature and in which are included means to record the fact that the circuit called has answered.

10. In a telephone system wherein two or more outlying circuits center in one exchange, a switchboard, an operators desk for said switchboard, an inductorium at said deskfor each of the circuits in the charge of the operator at said desk, and a connecting-plug also at said desk for each of said circuits, said plug having an electromagnet and means connected to the terminals of one coil of said inductorium for connecting the latter to the jack of a called circuit.

11. In a telephone system wherein two or more outlying circuits center in one exchange,

a switchboard, an operators desk for said switchboard, electromagnetic means at said desk for each of said circuits, a plug having an electromagnet, a local circuit in which said electromagnet is included, and means also included in said local circuit and adapted to be influenced by the electromagnetic means 01 the outlying circuits for closing said local circuit.

12. In a telephone system wherein two or more outlyingcircuits center in one exchange, a switchboard, an operators desk for said switchboard, a connecting-plug for eachof the circuits in the charge of the operator at said desk, an electromagnet for each of said plugs, a local circuit including said electromagnet and an annunciating-lamp, and meansalso included in said local circuit and influenced by the outlying circuit for closing the local circuit.

13. In a telephone system wherein two or more outlying circuits center in one exchange, a switchboard, a series of jacks for said switchboard each of which is provided with a softiron core, each of said outlying circuits being connected to one of said jacks and to a source of energy common to all of said circuits, an inductorium at said switchboard for each of said circuits, a plug at said switchboard for each of said circuits the circuit of which is in inductive relation to one coil of the inductorium of that circuit, and electromagnetic means carried by each of said plugs and adapted to be attracted by the soft-iron core of the jacks in which said plugs are inserted.

14. In a telephone system, a series of incoming circuits connected to the switchboard, part of said circuits being connected to one coil of an inductorium in inductive relation to a second inductorium, and a connecting-plug connected to one coil of said second inductorium and adapted to adhere to any of the jacks in the switchboard through electromagnetic action to thereby inductively connect two of said incoming circuits.

15. In a. telephone system wherein two or more outlying circuits center in one exchange, a switchboard for said exchange, a series of jacks for said switchboard, each jack connected to the terminals of an outlyingcircuit, a series 01 plugs for said switchboard, each plug in inductive relation to one of the outlying circuits, an inductorium for each of said cir cuits, an annunciating-lamp for each of said circuits, means in operative relation to said circuit to light said annunciating-lamp, and means in operative relation to the normal positions of said plugs to extinguish said annunciating-lamps.

16. In a telephone system wherein two or more outlying circuits centerin one exchange, aswitchboard, aseries of jacks for said switchboard, each of said jacks connected to the terminals of one of the outlying circuits, a series of plugs in inductive relation each to one of the outlying circuits, said plugs adapted to connect with the jacks of said switchboard and retain their position therein through electromagnetic action,- a series of inductoriums one coil of each of which is connected to one of the outlying circuits, means operatively connected to each of said circuits to annunciate the calling of said circuit, and means in operative relation to the normal position of the plug to terminate said annunciation.

17. In a telephone system embracing a series of outlying stations connected with their circuits to one central or exchange, a series of switchboards located at said exchange, each of said switchboards provided with terminals connected to the incoming circuits, a jack for each of said circuits consisting essentially of a soft-iron core and movable means to change the electrical connection of the circuit to which it pertains, a series of operatorsdesks each provided with a series of plugs connected each inductively to one of the incoming circuits, said plugs provided with electromagnetic means adapted to be energized when placed in connection with one of the jacks'on the switchboard and to remain energized throughout the period during which the circuit calling remains electrically closed, and an annunciating-lamp for each of said plugs, said annunciating-lamp being in operative relation to the circuit to which said plug pertains and adapted to be mad e operative through the closing of said circuit and inoperative through the removing of the plug from its normal position.

18. In a telephone system embracing a series of outlying stations connected with their circuits to one central or exchange, a series of switchboards located at said exchange, each of said switchboards provided with terminals connected to the incoming circuits, a jack for each of said circuits consisting essentially of a sot't-iron core and movable means to change the electrical connection of the circuit to which it pertains, a series of operators desks each provided with a series of plugs connected each inductively to one of the incoming circuits, said plugs provided with electromagnetic means adapted to be energized when placed in connection with one of the jacks on the switchboard and to remain energized throughout the period during which the circuit calling remains electrically closed, an annunciating-lamp for each of said plugs, said annunciating-lamp in operative relation to the circuit to which said plug pertains and adapted to be made operative through the closing of said circuit and made inoperative through the removing of the plug from its normal position, and a light-board provided with a series of indicating-lamps, each lamp being in operative relation to one of the incoming circuits and adapted to remain operative as long as said circuit remains closed.

19. In a telephone system embracing an exchange wherein the circuits of a series of outlying stations center, a source of electric current common to two or more of said electric circuits, jacks for said circuits adapted to change their electrical connection, means operatively related to each of said circuits to light two lamps, a light-board at which one of said lamps is located, an operators desk at which the other lamp is located, a plug for each of said circuits, said plug normally inductively related to said circuit, and adapted to connect inductively said circuit with a second circuit, a ringing-circuit, means operatively related to said plug to connect said ringing-circuit to said second circuit, and means operatively related to said second circuit and plug-circuit respectively to disconnect automatically said ringing-circuit.

20. In a telephone system embracing an exchange wherein the circuits of a series of outlying stations center, a source of electric current common to two or more of said electric circuits, jacks for said circuits adapted to change their electrical connection, means op eratively related to each of said circuits to light two lamps, one located ata light-board, and one located at or near an operators desk, a plug for each of said circuits, said plug inductively related to said circuit, and adapted to connect inductively said circuit with a second circuit, a ringing-circuit, means operatively related to said plug to connect said ringing-circuit to said second circuit, means operatively related to said second circuit and said plug-circuit respectively to disconnect automatically said ringing-circuit, a call-registering device, and means operatively related to said second circuit to make operative said registering device to thereby indicate the successful call of the first-named circuit.

In testimony whereof I hereby sign my name, in the presence of two subscribing witnesses, this 21st day of February, 1902.

ISIDOR KITSEE. WVitnesses:

EDITH R. STILLEY, CHAS. KRESSENBUOH. 

